Brake-valve.



No. 733,429. PATBNTED JULY 14, 1903. F. E. SGHMITT & L. E. MOORE.

BRAKE VALVE.

APPLICATION FILED-IAN. 22, 1903.

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UNTTED STATES rammed July 14, 1903.

PATENT OFFICE.

FREDERICK E. SOHMITT, on NE YORK, N. it, AND LEWIS E. noose,- o'r PHGENIXVILLE, PENNSYLVANIA.

BRAKE VA LV E.

SPECIFICATION forming part of Letters Patent Ne. 733,429, dated July 14, 1905.

Application filed January 22, 1903. Serial ITO-140,086. (No model.)

To all whom it puny concern:

Beit known that we,FREDERICK E. SCHMITT, residing at New York city, in the county and State of New York, and LEWIS E. IVIOORE, residing at Phoenixville, in the county of Chester and State of Pennsylvania, citizens of the United States, have invented a new and useful Improvement in Brake-Valves, of which the following is a specification.

Our invention pertains to air-brakes for railway-cars, more particularly to that class of brakes known as straight air-brakes, and has for its object the construction of an operating-valve by means of which the operator may at will increase ordecrease the force of the compressed air acting in the air-brake cylinder between the limits of zero or atmospheric pressure and the maximum pressure in the air-reservoir, and by which also the operator may possess in the pressure he applies to the handle of the valve a measure of the force applied to the brake.

Referring to the drawings, Figure l is a vertical section of the valve, and Fig. 2 an enlarged section of the lower part of the valve. Fig. 3 is a cross-section of the valve-body at the line 2 z in'Fig. 2.

In Figs. 1, 2, and 3 A and B are the two parts of the valve-body, which are bolted or screwed together. The upper part B incloses an upper cylindrical chamber 0 and a lower cylindrical chamber E of larger diameter. In the chamber 0 is fitted a piston D, movable up anddown bymeansof a leverQand handle R. The piston D has a smaller cylindrical downward prolongation T. In the chamber E is fitted a piston G. The lower part A of the valve-body incloses a long cylindrical chaniberF of smaller diameter than the chamber E. In the upper part of chamber F are fitted two pistons H and J, rigidly connected together and to the piston G by a stem K. The three pistons G, H, and J and the stem K form the main valve-plug. In the lower part of this main valve-plug is a passage g, leading from the space between the pistons H and J to the space below the piston J. In the lower part of the chamber F is fitted a piston L, with an upward tubular slotted prolongation M. This piston L is called the emergooey-plug. Below the piston L is a helical spring N, resting on the end of a plug 0,

screwed into the bottom of the castingA and adjustable therein and capable of being fasf tened by a jam-nut P. A bolt V, fastened into the plug 0, projects upward through the emergency-plug L, and its head being larger than the hole through L it limits the upward motion of the emergency-plug.

All of the pistons above described-viz, D, G, H, J, and Lmay be fitted with expansion-rings for preventing leakage, such as are used in pistons of ordinary steam-engines.

On one side of the body-casting A and formed integrally with this casting there is an air-chamber S,having an opening outward into which may be screwed a pipe leading from an air-reservoir. From the chamber S two ports lead into the valve-chamber F-an upper and smaller port a, termed the service-port, and a lower and larger port I), termed the emergency-port. On another side of the body-casting A, about opposite the air-chamber S, is a nipple U, into which may be screwed a pipe leading to the brakecylinder. This nipple has an opening 0, termed the brake-port, leading into the valve-chamber F. The port a is located a short distance higher than the port I). Near the upper'end of the valve-chamber F is an opening d, termed the exhaust-port, which leads from the valve-chamber F to the atmosphere. Near the lower end of the chamber E in the upper body-casting B is an open- ""leakage-port e, and the gage-portfare quite small. The emergency-port b and the brakeport 0 are substantially larger.

The operation of the valve is as follows: Suppose the air-pressure in the brake-cylinder is atmosphericthat is, that the brakes are released. Then since that portion'of the valve-chamber F lying between the pistons H and L is connected with the brake-cylinder by way of the nipple U and theport c the pressure in this space will also be atmospheric. The upper piston D is supposed to be at the upper limit of its travel in the position shown in the drawings, with its lower edge just above the gage-port f, and since this port opens to the atmosphere the chamber 0 therefore con'tains air at atmospheric pressure. The main valve-plug (G HJ K) is also at the upper limit of its travel in the position shown in the drawings. The lower edge of its piston H is just above the exhaustport 61, leaving this port open, and the upper edge of its piston J is just above the service-port a, closing this port. It will be noted that the lower part of the chamber Ecommunicates with the atmosphere by way of the leakage-port e, so that the air in this chamber is at atmospheric pressure. The brakecylinder communicates with the atmosphere by way of the brake-port c, the passage g, and the exhaust-port d. In the position of the valve referred to here, which is also the position shown in the drawings, Fig. 1, the emergency-plug L is at the upper limit of its travel and covers or blanks the emergencyplug 1). Now let it be desired to apply the brakes. By means of the handle R and lever Q the operator moves the piston D a short distance downward. In the first portion of its travel the piston D closes the gage-port f, and by further downward motion it compresses the air in the chamber 0. This air presses with equal intensity per square inch downward upon the piston G of the main valve-plug; but the total force with which the air presses upon G is greater than the force which presses the piston D downward on account of the difference in area of the exposed faces of the pistons D and G. This arrangement of parts constitutes anelastic link between the pistons D and G. The downward pressure upon piston G causes the main valve -plug to move downward until it rests upon the projection M of the emergency-plug L, where it is prevented from moving farther down by the spring N. As the main valve-plug moves down it first closes the exhaust-port (Z, and on further downward motion it uncovers the serviceport a. The relative position of the ports a and d and the pistons H and J is such that the exhaust-port (Z is entirely closed by the piston H, and the valve-plug must travel a small distance farther down before the piston J begins to uncover the SBI'VICG-POIKG. WVhen the port a is uncovered,-compressed air from the air-reservoir enters by way ofthe air-chamber S and the port a into the space between the pistons H and J, passes thence'through the passage g into the space;

below the piston J, and thence by way of the brake-port c and the connecting-pipe to thebrake-cylinder. Air continues to flow in this way, raising the air-pressure in the brakecylinder and applying the brakes with correspondingforce until the pressure in the brakecyllnder has reached a certain point, depending upon the downward pressure which the operator applies to the handle R, as follows: The air-pressure in the air-reservoir remains or by suitable means is maintained practically constant. When air flows through the port a in the manner described, this port, which has previously been described as being quite small, throttles the air, so that while the air is flowing the pressure between the pistons H and J is less than the pressure in the reservoir. The passage g, the port 0, and the other connections to the brake-cylinder are large enough so that no considerable throttling takes place in them, and the pressure of the air may therefore be considered substantially uniform from the inner end of the port a to the brake-cylinder. Now the air between the pistons H and J presses equally upward and downward; but the air below the piston J presses upward with a force depending upon the pressure of the air and upon the area of the exposed face of the piston J. When this upward pressure becomes greater than the downward pressure caused by the air in the chamber 0 acting upon the piston G, then the entire main valve-plug will be moved upward. As it moves up the piston J covers the service-port a, and thus cuts off the air entering from the reservoir. No further increase of pressure in the brakecylinder then takes place and the valve-plug becomes stationary. It should be noted that as the valve-plug moves upward the air contained in the chamber C is compressed between the pistons G and D. This increases the downward pressure on G, whereas the upward pressure on the piston J remains practically constant as soon as the inflow of compressed air through the port a is cut off.

In consequence the main plug-valve moves up so as to cover the service-port a, and is then brought to rest by the balancing of the pressure downward upon G with the pressure upward against J. Thus it is clearly seen that the final pressure attained in the brakecylinder depends directly upon the force with which the piston'D was pushed downward. In other words, the result of moving the piston D downward a definite amount is to apply the brakes with a definite force, corresponding to a definite air-pressure in the brake-cylinder, which pressure is less than that in the air-reservoir.

To show another phase of the operation of this valve, suppose that in the condition above described it be desired to increase the force with which the brakes are applied. The operator moves the piston D a little farther down, thereby increasing the compression of the air in the chamber 0 and correspondingly increasing the force acting downward upon the piston G. The main valve-plug is now not in balance and it moves downward, opening the service-port a, and thus permitting compressed air from the air-reservoir to enter the brake-cylinder. The pressure in the latter rises and the brakes are applied with increased force. At the same time the airpressure below the piston J rises, so that soon the upward force on the main valve plug becomes again slightly greater than the downward pressure upon G, at which time the valve-plug moves upward, closes the port 4 cape.

a, and comes to rest in the manner already described. Thus by moving the piston D downward a definite additional amount a definite increased force of application of the brakes results.

Further, suppose that in the balanced condition resulting from either of the above proceedings it be desired to diminish the force with which the brakes are applied. For this purpose the operator moves the piston D upward a short distance, thereby decreasing the compression of the airin the chamber 0, and consequently decreasing the pressure downward upon the piston G. This pressure is now less than the upward pressure of the air below the piston J, and as a result the main valve-plug moves upward, thereby uncovering the exhaust-port (Z. The air in the brake-cylinder then escapes to the atmosphere by way of the brake-port c, the passage g, and the exhaust-port d. Thereby the air-pressure in the brake'cylinder islowered- 11. e., the force with which the brakes are applied is decreased. Correspondingly the pressure of the air below the piston J is lowered as the release of the air through the exhaust-port (Z continues until the pressure upward against the piston J is reduced below the downward pressure upon the piston G. \Vhen this point is reached, the main valve-plug is forced downward and its piston H closes the exhaust-port cl, stopping the release of the air from the brake-cylinder. The valve-plug then comes to rest by an action similar to though the reverse of the balancing action already described. Thus as the result of a definite upward motion of the piston D the force with which the brakes are applied is decreased a definite amount.

Lastly, suppose it be desired to release the brakes entirely-i. e., to withdraw the brakeshoes from. the wheels by reducing the airpressure in the brake -cylinder to atmospheric. The operator moves the piston D upward to its original position (shown in the drawings, Fig. 1,) and by an action precisely similar to that described above the main valve-plug moves upward, thereby uncovering the exhaust-port d and permitting the compressed air in the brake-cylinder to es- The pressure of the air in the chamber 0 is now atmospheric, since the gage-port f connects this chamber with the atmosphere. Consequently the main valve-plug is not again forced downward and the air in the brake-cylinder continues to escape, so that its pressure is reduced to atmospheric.

No reference has been made in the preceding description to the function of the leakageport 6. It is clear that if any pressure of air otherthan atmospheric could exist in the chamber E it would interfere with theoperation of the valve, as above described. Now in applying the brakes the space between the pistons H and J is filled with compressed air, and if the piston H should fit its chamber imperfectly some of this air might leak over into the chamber E. The port 6 serves the purpose of immediately carrying ed to the atmosphere any such leakage. However, the port e has another function which we consider important. When the main valve-plug moves upward or downward, the volume of air inclosed between the pistons G and H is altered, and the excess of deficiency is made up by air passing through the port 6; but this port is quite small, so that air cannot pass through it very rapidly. As a result there is a momentary slight change in the airpressure in the chamber E, which acts upon the piston G in a direction-opposed to the motion of the valve-plug. Thus the port e acts to cushion the motion of the main valve-plug and to prevent it from moving with excessive velocity.

It is possible by means of the valve shown to produce a more sudden application of the brakes than is possible by the regular operation described in the preceding. As was explained, the service-portais small, so thatit produces a considerable throttling of the air which passes through it, and for this reason the application of the brakes in the manner described is somewhat gradual. While this is a desirable condition on most occasions when the brakes are used, circumstances may arise when it is an advantage to be able to apply the brakes as rapidly and with as much force as possible. The construction of the valve shown enables this to be done, as follows: The operator moves the piston D downward until its prolongation T strikes the upper surface of the piston G and forces the main valve-plug downward. This latter then strikes the prolongation M of the emergencyplug L and in turnforcesLdownward against the resistance of the spring N. As the emergency plug L moves down it uncovers the emergency-port b, which is a large opening,

and thus permits compressed air to pass directlyand withoutanyconsiderable throttling from the air-reservoir to the brake-cylinder. This action produces the maximum braking force in a much shorter time thanis possible by the regular action previously described on account of the absence of throttling of the air.

It should be remarked that the hole through which the rod V passes through the emergency-plug L is larger than the rod, so as to permit of free passage of air from the upper to the lower side of the plug L.

The preceding description and explanation show the mannerof operation of one form of our invention; but we do not limit ourselves to the specific construction or arrangement shown.

tect by Letters Patent,

1. A valve for operating an air-brake system, consisting of a valve-chamber connecting respectively with an air-reservoir and an air-brake cylinder, a valve-plug movable in said chamber, means by which the operator may move said plug so as to open communication through the valve between the air-reservoir and the air-brake cylinder, and means actuated by the pressure in the air-brake cylinder for moving said plugin the reverse direction, in combination substantially as described.

2. A valve for operating an air-brake system, consisting of a valve-chamber with a port communicating with an air-reservoir, an opening leading to an air-brake cylinder, a valve plug or cover for opening and closing said port, means for moving said plug in either direction at the will of the operator so as to open or close said port, and means by which the air-pressure in the brake-cylinder may automatically move the plug so as to close said port, in combination substantially as described.

3. A valve for operating an air-brake system, consisting of a valve-chamber connecting respectively with an air-reservoir and an ainbrake cylinder, a valve-plug movable in said chamber, means by which the operator may move said plug so as to open communication through the valve between the airreservoir and the air-brake cylinder, and means actuated by the pressure in the airbrake cylinder for moving said plug in the reverse direction, together with means for releasing air from the brake-cylinder, in combination substantially as described.

4. A valve for operating an air-brake system, consisting of a valve-chamber with an opening leading from said chamber to an airbrake cylinder, two ports, one leading from an air-reservoir and the other to the atmosphere, a valve-plug movable in said chamber to open or close said ports, means actuated by the operator for moving said plug so as to open the port admitting air from the reservoir into the valve,'means actuated by the pressure in the brake-cylinder for moving said plugin the reverse direction so as to close said port, and means by which the operator may move the plug into another position so as to open the port leading to the atmosphere, in combination substantially as dedescribed.

5. A valve for operating an air-brake system, consisting of a valve-chamber with an opening leading to an air-brake cylinder, an admission-port leading from an air-reservoir and a release-port leading to the atmosphere, means actuated by the operator for opening or closing said ports, and means actuated by the pressure in the valve-chamber for closing the admission-port, in combination substantially as described.

(3. A valve for operating an air-brake system, consisting of a valve-chamber with two ports, one leading from an air-reservoir and the other to an air-brake cylinder, means for opening either one of said ports so as to admit air through the valve-chamber from the air-reservoir to the brake-cylinder and for closing said port at will of the operator, and

means actuated by the pressure in the brake cylinder for closing said port, in combination substantially as described.

7. A valve for operating an air-brake system, consisting of a valve-chamber having three ports, one leading from an air-reservor, another leading to an air-brake cylinder and a third to the atmosphere, means actuated by the operator for opening and closing any of these ports so that air may be admitted from the reservoir into the brake-cylinder and the admission cut off as desired, or so that air may be released from the brake-cylinder into the atmosphere, and means actuated by the pressure in the brake-cylinder for cutting off the admission, in combination substantially as described.

8. A valve for operating an air-brake system, consisting of a valve-chamber with two ports connecting respectively with a brakecylinder and with the atmosphere, a valve plug or cover for opening and closing either or both of said ports, means for admitting air from an air reservoir into the brake-cylinder, means actuated by the pressure in the brakecylinder for moving said plug so as to uncover said ports and allow air to pass from the brake-cylinder to the atmosphere, and means for closing said port or ports when the pressure in the brake-cylinder has become reduced to any desired point, substantially as described.

9. In a valve for operating an air-brake system, the combination with a valve-chamber having ports, and a valve plug or cover for opening and closing said ports, of an operating handle or lever, and an elastic link between the said lever and the said plug, the lever and elastic link being adapted to be moved so as to exert upon the said plug a force of any desired amount which force may be increased or decreased by suitable movement of the operating-lever.

10. In a valve for operating an air-brake system, the combination with a valve-chamber, of a valve-plug having two exposed faces of different area, one of which is acted upon by the air-pressure in the brake-cylinder applying a force to the plug in one direction, and the other by an adjustable air-pressure applying a force to the plug in the opposite direction.

11. A valve for operating an air-brake system, consisting of a valve-chamber with ports, a valve plug or cover for opening or closing said ports, an operating handle or lever connected by an elastic link with the said plug and adapted to move the said plug in one direction, and means actuated by the pressure in the brake-cylinder for moving said plug in the opposite direction.

2. A valve for operating an air-brake systern, consisting of a valve-chamber having ports connected respectively with an air-reservoir, with a brake-cylinder and with the atmosphere, a valve plug or cover adapted to open or close sa-id ports, an operating handle or lever connected byan elastic link with the said plug and adapted to apply a variable force of any desired amount to said plug, said force tending to move said plug from the position where it connects the brake-cylinder port with the atmosphere-port to the position where all ports are closed, or farther to the position where it connects the air-reservoir port with the brake-cylinder port, and means whereby the air-pressure in the brake-cylinder applies a force to said plug tending to move it in the opposite direction, said force being greater or less according as the airpressure in the brake-cylinder is greater or less.

13. A valve for operating an air-brake system, consisting of a valve-chamber having ports, a main valve plug or cover for opening and closing said ports, means for moving said main plug so as to establish communication through the valve between an air-reservoir and a brake-cylinder, and means actuated by the pressure in the brake-cylinder for moving said main plug in the opposite direction, in combination, substantially as described, with an emergency-plug and means actuated by the operator for moving the emergencyplug so as to establish free communication through the valve between the air-reservoir and the brake-cylinder.

In testimony whereof we have signed our names to this specification each in the presence of two subscribing witnesses.

FREDERICK E. SOHMITT. LEWIS E. MOORE.

\Vitnesses as to the signature of Frederick E. Schmitt:

MOSES NELSON BAKER, CHARLES W. REINHARDT.

Witnesses as to the signature of Lewis E. Moore:

FRED GEO. LIPPERT, WALTER R. OKESON. 

